Gliese 317

Gliese 317 is a red dwarf approximately 50 light-years away in the constellation of Pyxis. As of 2011, two extrasolar planets have been confirmed to be orbiting the star.[2][4] Photometric calibrations and infrared spectroscopic measurements[3] indicate that the star is enriched in heavy elements compared to the Sun.

Gliese 317
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Pyxis
Right ascension  08h 40m 59.2056s[1]
Declination −23° 27′ 22.5986″[1]
Apparent magnitude (V) 11.98
Characteristics
Spectral type M2.5V[2]
Variable type none reported
Astrometry
Radial velocity (Rv)87.8[2] km/s
Proper motion (μ) RA: −461.162±0.139[1] mas/yr
Dec.: 805.571±0.126[1] mas/yr
Parallax (π)65.7744 ± 0.0557[1] mas
Distance49.59 ± 0.04 ly
(15.20 ± 0.01 pc)
Other designations
GJ 317, LFT 538, LHS 2037, LPM 296, LTT 3215
Details
Mass0.42 ± 0.05[2] M☉
Temperature3510 ± 50[2] K
Metallicity [Fe/H]+0.3[2][3] dex
Database references
SIMBADdata
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia		data

Planetary system

In 2007, a jovian planet (designated Gliese 317 b) was announced to orbit the star.[4] The planet orbits about 95% the distance between Earth to the Sun. Despite of this, it takes about 1.9 years, due to the lower mass of the central M dwarf. Astrometric measurements on Gliese 317 provided a significant update to the distance, putting the star at 15.3 pc, which is 65% further out than previously assumed.[2] Using mass-luminosity calibrations, the new distance implies the star is significantly more massive and so are the planet candidates. The same astrometric measurements allowed to constrain the orbital inclination and put an upper limit to the mass of Gliese 317 b (98% confidence level) of 2.5 M_jup.

The second planet in the system was also confirmed with the additional new RV measurements, but the period and orbital parameters of Gliese 317 c are still very uncertain (P>2000 days).[2] A stability analysis on this putative system suggest that the pair of gas giant planets are in a 4:1 mean motion resonance.[5] The second planet, remote from its host star, is a good candidate for direct imaging.[2]

The Gliese 317 planetary system[2]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b >1.81 ± 0.05 MJ 1.148 692.0 ± 2 0.11 ± 0.05 — —
c (unconfirmed) ≥1.6 MJ ≥5.5 ≥7100 unknown — —

See also

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Anglada-Escude, Guillem; et al. (2012), "Astrometry and radial velocities of the planet host M dwarf Gliese 317: new trigonometric distance, metallicity and upper limit to the mass of Gliese 317 b", The Astrophysical Journal, 764 (1): 37A, arXiv:1111.2623, Bibcode:2012ApJ...746...37A, doi:10.1088/0004-637X/746/1/37
  3. Terrien, Ryan C.; et al., "An H-band Spectroscopic Metallicity Calibration for M Dwarfs", The Astrophysical Journal, 747: L38, arXiv:1202.1800, Bibcode:2012ApJ...747L..38T, doi:10.1088/2041-8205/747/2/L38
  4. Johnson, J. A.; et al. (2007), "A New Planet Around an M Dwarf: Revealing a Correlation between Exoplanets and Stellar Mass", The Astrophysical Journal, 670 (1): 833–840, arXiv:0707.2409, Bibcode:2007ApJ...670..833J, doi:10.1086/521720
  5. Rory Barnes; Richard Greenberg (2008). "Extrasolar Planet Interactions". arXiv:0801.3226v1 [astro-ph].


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